The Machinability of Aluminum 1 Group 32

content Introduction Machining of aluminum The Machining Process 1-Forms of Aluminum Chips 2- Surface of Machined Aluminum Alloys 3- Tool wear and tool life 4- Cutting Force for Machining Aluminum Applications References 2

Introduction Definition of Machinability : The machinability of a material can be defined as the ease with which it can be machined. This depends on the physical properties of the material, as well as on the cutting conditions. 3

Why we use Aluminum in machining? Aluminum alloys are characterized by two main properties: 1- The cutting temperature. (a maximum of 600 °C compared with 1000 °C for steels) 2-Their low density reduces inertia forces and allows high rotation speeds. 4

Machining of aluminum Aluminum alloys are among the most commonly used lightweight metallic materials as they offer a number of different interesting mechanical and thermal properties. They are relatively easy to shape metals, especially in material removal processes, such as machining. 5

Machining of aluminum Aluminum alloys as a class are considered as the family of materials offering the highest levels of machinability Aluminum alloys possess physical properties for good machinability, in terms of (cutting tool life- greater productivity - low specific cutting forces.) 6

The Machining Process 7

1-Forms of Aluminum Chips 1-Forms of Aluminum Chips It is an important criterion, especially when one bears in mind the very large volume of chips created while machining aluminum. Pure aluminum and soft wrought alloys produce extremely long chips, making it essential to introduce chip breakers on the tools. High-strength wrought alloys (e.g. AlMg5(5019), AlMgSi1(6082) present no problems as far as chip form is concerned. Hypoeutectic casting alloys (G-AlSi8Cu3, G-AlSi10Mg etc.) lead to the formation of short coiled and spiral chips which can be removed easily. Eutectic casting alloys (G-AlSi12) tend to produce longer chips. 8

1-Forms of Aluminum Chips 1-Forms of Aluminum Chips 9

2- Surface of Machined Aluminum Alloys 10

3- Tool wear and tool life The tool wear while machining aluminum occurs due to abrasion of the free surface. Wear increases with the number of large hard particles which are embedded in the aluminum workpiece. Such particles could be primary precipitations of silicon particles in a hypereutectic alloy. This is the reason that aluminum castings cause high wear of tools. The wear is extremely high in the case of cast. Wrought alloys with low silicon contents cause minimum tool wear. 11

3- Tool wear and tool life Tool life is the time the cutting edge can be used until it is worn out The correlation between cutting speed, v, and tool life, T, V c =C.T 1/k 12

4- Cutting Force for Machining Aluminum Different alloys have varying specific cutting forces, the variations being however, relatively small. In general one can assume that the specific cutting force for aluminum is about 30 % that of steel. 13

6- Cutting Force for Machining Aluminum 14

Applications Applications carburetor parts, 15

Applications Applications 16 clock parts

Applications Applications 17 gears, knobs, camera parts, gears, pipe stems and filters, radio parts, mobile phones, tripod fittings, machine parts. Aluminum gears for Polaris Industries (Racing) Apple 6000 series aluminum phones

Aluminum Alloys suitable for machining - EN is referred to as a free machining alloy due to its excellent machining properties. -The most common tempers for 2011 aluminum are: T3 – Solution heat treated, cold worked and naturally aged T6 – Solution heat treated and artificially agedaluminum 18

Aluminum Alloys suitable for machining when greater corrosion resistance is required leads to 6262 T9 being used with excellent mechanical properties and good corrosion resistance. -Both 2011 and 6262 are commonly supplied in bar form. -When machining of plate aluminum is required, the grade selected is Alloy 6082 A popular heat treatable alloy. Medium strength is combined with good, welding, corrosion resistance and machinability. 19

Tools for aluminum machining 1. Cutting force Important characteristics of PLANSEE TIZIT inserts: Rake angle > 25°increasing the rake angle by one degree the cutting force is reduced by ~1.5%. Sharp, uniform cutting edge. Extra-smooth rake face. 2. Tool life Important characteristics of PLANSEE TIZIT inserts: extremely wear resistant hard metal grades optimized coating extra-smooth rake face 20

Tools for aluminum machining 3. Surface finish Important characteristics of PLANSEE TIZIT inserts: extra-smooth rake face optimized micro-geometry of the cutting edge fine grain substrates 4. Chip formation Important characteristics of PLANSEE TIZIT inserts: aluminum specific chip grooves reduced friction between chip and rake face 21 Unfavorable Favorable

TOOLS FOR ALUMINUM MACHINING 1 - Very good machinability 5 - Bad machinability 22

References Machining and Machinability of Aluminum Alloys, Author: V. Songmene, R. Khettabi, I. Zaghbani, J. Kouam, and A. Djebara, École de technologie supérieure (ÉTS), Department of Mechanical Engineering, Canada. TALAT Lecture 3100, prepared by P. Johne, Aluminium-Zentrale e.V., Düsseldorf. PLANSEE TIZIT company, Plansee Tizit Aktiengesellschaft,Tools for aluminium machining. 23